A variety of chemical compounds have been proposed and actually used for the purpose of regulating the growth of plants with a chemical substance, that is for the purpose of so-called "chemical control" of the growth of plants. Thus, maleic hydrazide (MH), N,N-dimethylaminosuccinamide (known as Daminozide) and 2-chloroethyl trimethyl ammonium chloride (known as Chlormequat) have been used for retardation of the growth of plants, for control of emergence of sideshooting or for prevention of the lodging of plants. These known compounds, however, have various drawbacks such that their applications are restricted in respect of the locus, nature of plants and time which can effectively be treated therewith, that their plant growth regulating effects are insufficient or unstable, that they are phytotoxic, and/or that they are too expensive. Further, in the application of a plant growth regulating agent to lawns, it is in general desirable to use such kind of a regulating agent as to exhibit a growth retarding effect with little or minimum fluctuation thereof over a wide variety of the kinds of lawns for making the mowing of lawns easier because a plurality of species of lawns are often blended for seeding in order to adapt various environmental stresses occurred such as plant diseases and harmful insects, wheather and soil conditions, etc. Most of known types of plant growth regulators do not meet such applications.
During our extensive investigations being made with the intention of providing new plant growth regulators which have little or no such drawbacks of the known regulators as above-mentioned, we have already found that a class of cyclohexane derivatives which we have first synthesized exhibit significant plant growth regulating activities without substantially suffering from the above-said drawbacks. The cyclohexane derivatives are those having the general formula: ##STR4## wherein R represents a hydrogen atom or an alkyl, alkylthioalkyl, or unsubstituted or substituted phenyl group; and R.sup.1 represents an alkyl, unsubstituted or substituted benzyl, phenethyl, phenoxymethyl, 2-thienylmethyl, alkoxymethyl or alkylthiomethyl group, and their salts (refer to Japanese patent application Kokai Nos. 164543/83 and 196840/84 and U.S. Pat. No. 4,560,403).
Another class of cyclohexane derivatives is disclosed in European patent application Prepublication No. 0126713 (Application Nos. 84810233.1 filed by Ciba-Geigy AG) and corresponding Japanese patent application Kokai No. 231045/84), which is represented by the general formula: ##STR5## wherein A is --OR.sub.2 or --NR.sub.3 R.sub.4 ; B is --OH, --NHOR.sub.1 or a metal or ammonium salt thereof; R is C.sub.1 -C.sub.6 alkyl or C.sub.3 -C.sub.6 cycloalkyl, unsubstituted or substituted by halogen, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 alkylthio; R.sub.1 is C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 haloalkyl, C.sub.3 -C.sub.6 alkenyl, C.sub.3 -C.sub.6 haloalkenyl or C.sub.3 -C.sub.6 alkynyl; R.sub.2, R.sub.3 and R.sub.4 each are hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 haloalkyl, C.sub.2 -C.sub.10 alkoxyalkyl, C.sub.2 -C.sub.10 alkylthioalkyl, C.sub.3 -C.sub.6 alkenyl, unsubstituted or substituted by halogen, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 alkylthio, C.sub.3 -C.sub.6 alkynyl, phenyl or C.sub.1 -C.sub.6 aralkyl where the phenyl nucleous may be unsubstituted or substituted by halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 haloalkyl, nitro or cyano; or R.sub.3 and R.sub.4 may form together with the nitrogen atom to which they are bonded a 5- or 6-membered heterocyclic group which may further contain oxygen or sulfur hetero atom.
As far as we, the present inventors, have synthesized and tested two particular compounds amongst many examples of the compound of the above formula according to the European patent application prepublication No. 0126713, such cyclohexane derivatives of the above formula where A is --OC.sub.2 H.sub.5, B is --NHOC.sub.2 H.sub.5 and R is --C.sub.3 H.sub.7 -n; and where A is --OC.sub.2 H.sub.5, B is --NHOCH.sub.2 CH.dbd.CH.sub.2 and R is --C.sub.3 H.sub.7 -n do not necessarily have satisfactorily high activities on applications for the plant growth regulation.
We have further continued our investigations on the preparation and application as plant growth regulators of a wide variety of new cyclohexane derivatives and their salts, and have now found a new class of cyclohexane derivatives to be excellent plant growth regulators particularly in that their plant growth retarding activities are even less variant over various kinds of lawns than those of the known cyclohexane derivatives we propose and in that they have little or no such drawbacks of the conventional plant growth regulators as above-mentioned.